Electric-furnace construction



Jan. 1, 1929. J 1,697,188

G. KELLER ET AL swcmc runmcm consmvcwzon Filed May 9, 1927 Patented Jan.1,1929.

, UNITED STATES PATENT OFFICE.

GO'ITLIEB KELLER, OF BRUGG, AND ERNST W132, 015 BADEN, SWITZERLAND, AS-SIGNORS T0 AKTIENG ESELLSCHAFT BROWN BOVERI & CIE, OF BADEN, SWITZER-LAND, A JOINT-STOCK QOMPAN Y 01 SWITZERLAND.

ELECTRIC-FURNACE CONSTRUCTION.

Application filed Kay 9, 1927, Serial No. 189,877, and in Germany June7, 1926.

This invention relates to electric furnaces of the melting type and hasto do particularly with the construction of means for supporting andadjusting the electrodes, whereby their feed is controlled incident tooperation of the furnace.

Thegeneral object of the invention is the provision of an adjustableelectrode supporting apparatus which will aii'ord effective insulationbetween the electrode carrier, which is electrically charged, and theearthed members whereby the carrier is supported and operated. l

Another object is the provision of a construction which will beeffective to avoid deterioration of the insulation by heat and wear, andthus aflord reliable protection for the portions of the apparatus whichare earthed or which are likely to be touched by persons or otherobjects.

Other and further objects willbe pointed out or indicated hereinafter,or will be apparent to one skilled in the art upon anunderstanding ofthe invention or its employment in practice.

In the drawing forming a part of this specification, We illustratecertain arrangements of structure embodying the invention, but it is tobe understood that these are susceptible of various modifications inarrangement and detail, withoutdeparting from the scope of the inventionindicated in the appended claims.

In said drawing,

Fig. 1 is a diagrammatic illustration in the nature of a sectionalelevation of apparatus in which the invention is embodied;

Fig. 2 is a detail inthe nature of a diametrical section of one of thewheels for the carrier 'frame Fig. 3 is a similar section of a modifiedconstruction of the frame-carrying wheels;

Fig. 4 is a detail in the nature of a sect-ion of a connection betweenthe electrode-carrying frame and its operating means; and

Fig. 5 is a similar'detail of another form of such connectionConsiderable difiiculty is ex erienced in preserving proper insulationetween the movable electrode holders ofelectric melting furnaces and theassociated portions ofthe apparatus which are earthed or which areeasily accessible and likely to be touched by persons or objects in thevicinity of the furnace. These difiiculties arise from the necessity ofaffording secure support and accurate guidance for the electrodes, whichare themselves heavy, and the destructive effects of high temperaturesupon the insulating material. The present invention solves thedifliculty by a new arrangement of the electrode supporting andoperating apparatus, whereby the necessary strength is afforded in thesupporting structure, accu-v racy in the guidance of the electrode ismaintained, and the insulating material is safeguarded against thedestructive ei'fects of the furnace temperatures. The nature of the in-'having flanged wheels 17 which run on and are guided in guide channels18 supported inan upright position adjacent the furnace by brackets 19.Hydraulic power cylinder 20 constitutes part of the operating means foreffecting and controlling the vertical position of the carriage on theguides l8,.and hence the position of the electrode and its feed towardor from the furnace. The piston of the hydraulic cylinder 20 isconnected to the carriage by 'a rod 21 and a connection 22. I Thecylinder, of course, has pipe connections to other apparatus, such asthe means for furnishing and regulating the supply of pressure fluid, soit is highly important thatthe cylinder, as well as the guides 18, befully insulated from the heavy current supplied to the carrier 14.Heretofore, it has been customary to provide an insulated COllI1C tionbetween the carrier 14 and the arm 16, or in the latter, for thispurpose. When so arranged, however, the insulating material is'thenexposed to high temperatures, and also to mechanical pressures, whichhas frequentlyresulted in the deterioration or breaking down of'theinsulation and loosening of the mechanical mounting of the carrier. Bythe present invention the insulat-.

ing material is removed from the zone of layer of suitable insulatingmaterial 24, such as mica. Thus a strong mechanical structure isprovided, which is Well qualified to support the carriage, withefiective insulation between the carriage and the guides. The edges ofthe mica insert are protected by rings of a suitable insulatingmaterial, such as bakelite, suitably molded or. othera wise securedagainst the faces of the wheel members. In the construction asillustrated in Fig. 3, there are provided cooperating hub portions 17 cand 17 having synclinal peripheral faces for clamping cooperation withsynclinal inner faces of the rim portion 17 The insulating material 26is inserted be tween these cooperating faces of the hub and rim membersand the'hub member 17 drawn up toward the member 17 by bolts 27, so asto securely clamp the insulating material between the rim and hubmembers.

Connections for the operating rod and the carriage are illustrated inFigs, 4 and 5. In the construction illustrated in Fig. 4, the operatingrod '21 carries a yoke member 28 which is shrunk onto a bushing 29 withan interposed sleeve 30 of strong insulating material, such as mica. Thebushing is connected .to the carriage by a stud 31. In this fashion,

the operating mechanism is effectively insulated from the carriage.struction illustrated in Fig. 5, the rod 21 carries a split clampingmember 32, which is clamped down on the stud 31by bolts 34, witha'sleeve 35 of insulating material interposed between the clamp and thestud.

With the apparatus constructed in conformity with this invention,therefore, the insulating material is safeguarded against hightemperatures and mechanical wear, and

its security and durability thereby materially enhanced, with the resultthat the grounded portions of the mechanism are afforded betterprotection against voltage and the electrode is aiforded more accurateguidance and stable support,

'Whatwe claim is:

1. In electric furnace apparatus, in combination, an electrode holder, acarriage for same, a guide on which the carriagetravels, and insulatingmaterial between the carriage In the conand guide for preventingtransmission of current from the holder to the guide.

2. In electric furnace apparatus, in comwhich the carriage travels,insulating ma-- terial between the carriage and guide, operatingmechanism for shifting the carriage on the gulde, and insulatingmaterial between the operating mechanism and carriage.

4. In electric furnace apparatus, 1n combination, an electrode holder, acarriage supporting the holder, a guide for the carriage, and wheels onwhich the carriage travels on the guide. paid wheels having incorporatedtherein dielectric material insulating the guide from the carriage.

In electric furnace apparatus, in combination, an electrode holder, acarriage supporting same, operating mechanism for shifting the carriage,and a connection between the operating mechanism and carriage wherebymovement is transmitted to the latter from the former, said connectionhaviifg incorporated therein dielectric material insulating theoperating mechanism from .the carriage.

6. In electric furnace apparatus, in combination, a carriage forsupporting anelectrodc, a guide for the carriage, and a wheel having ahub portion connected to the car- .riage anda rim portion running on theguide and dielectric material insulating the rim portion from the hubportion.

7. In electric furnace apparatus, in combination, a carriage forsupporting an electrode, and a guide and operating mechanism havinginsulated operative connection with the carriage.

8. In electric furnace apparatus, in combination, a vertically extendingguide disposed to one side of the furnace, a carriage having anelectrode-supporting arm extending from theguide to a position over thefurnace, and insulating means between the carriage and guide andoperating to guide said carriage for traveling movement on said guideand to insulate said carriage from said guide.

' In testimony whereof we have hereunto subscribed our names this 21 dayof April, A. D. 1927, atZurich, Switzerland.

GOTTLIEB KELLER. ERNST WIRZ.

